March 28 (Reuters) - The search for flight MH370, the Malaysian Airlines jetliner that vanished over the South China Sea on March 8, has involved more than two dozen countries and 60 aircraft and ships but been bedevilled by regional rivalries.

While Malaysia has been accused of a muddled response and poor communications, China has showcased its growing military clout and reach, while some involved in the operation say other countries have dragged their feet on disclosing details that might give away sensitive defence data.

Several countries in the region, including China, Malaysia, Indonesia and the Philippines, are engaged in a series of territorial disputes in the South China Seas, with control of shipping lanes, fishing and potential hydrocarbon reserves at stake.

With the United States playing a relatively muted role in the sort of exercise that until recently it would have dominated, experts and officials say there was no real central coordination until the search for the plane was confined to the southern Indian Ocean, when Australia largely took charge.

Part of the problem is that Asia has no NATO-style regional defence structure, though several countries have formal alliances with the United States. Commonwealth members Malaysia, Singapore, New Zealand and Australia also have an arrangement with Britain to discuss defence matters in times of crisis.

“There is ... a pressing need for regional security structures to take a few leaps forward,” said air Vice Marshal Michael Harwood, a retired RAF pilot and former British defence attache in Washington DC.

The risk, he said, was that the search instead became seen a national “test of manhood” and driver of rivalry. Already, several governments have been openly competing in announcing findings and satellite images.

The jet, which disappeared en route from Kuala Lumpur to Beijing, was last officially detected hundreds of miles off course on the wrong side of the Malaysian peninsula.

As mystery deepened over the fate of the Boeing 777 and its 239 passengers and crew, most of them Chinese, it became clear that highly classified military technology might hold the key.

But the investigation became deadlocked over the reluctance of others to share sensitive data, a reticence that appeared to harden as the search area widened.

“This is turning into a spy novel,” said an envoy from a Southeast Asian country, noting it was turning attention to areas and techniques few countries liked to publicly discuss.

CHINESE CLOUT

With five Chinese ships heading to a new search area in the Indian Ocean on Friday, experts say China is revealing military capabilities it lacked just a handful of years ago.

Chinese officials have also spoken of the growing number of satellites it has put to the task, a sensitive topic nations rarely disclose.

“A decade ago, China wouldn’t even have been in this game at all,” says Christopher Harmer, a former U.S. naval aviator and search-and-rescue pilot, now senior fellow at the Institute for the Study of War in Washington DC. “It really shows how far they have come, much, much faster than most people expected.”

Ultimately, the only country with the technical resources to recover the plane - or at least its black box recorder, which could lie in water several miles deep - may be the United States. Its deep-sea vehicles ultimately hauled up the wreckage of Air France 447 after its 2009 crash into a remote region of the South Atlantic.

So far, Washington has sent two Poseidon maritime reconnaissance aircraft to the southern Indian Ocean search as well as an underwater drone and its Towed Pinger Locator, specifically designed to detect the signals from black boxes. The locator will be fitted to an Australian ship.

RADAR POKER

While Kuala Lumpur has been forced to reveal some of the limits and ranges of its air defences, the reluctance of Malaysia’s neighbours to release sensitive radar data may have obstructed the investigation for days.

At an ambassadorial meeting in the ad hoc crisis centre at an airport hotel on March 16, Malaysia formally appealed to countries on the jet’s possible path for help, but in part met with polite stonewalling, two people close to the talks said.

Some countries asked Malaysia to put its request in writing, triggering a flurry of diplomatic notes and high-level contacts.

“It became a game of poker in which Malaysia handed out the cards at the table but couldn’t force others to show their hand,” a person from another country involved in the talks said.

It was not until a week later that Malaysia announced a list of nations that had checked their archives.

Beijing, meanwhile, was dramatically upping its game.

Its ability to deploy forces deep into the southern hemisphere is particularly striking. Beijing has sent several deployments into southern waters in recent months, including warship visits to New Zealand and South America, while its icebreaker “Snow Dragon” helped rescue personnel from a trapped Russian icebreaker in the Antarctic late last year.

“China are deploying because that’s what great powers do, and there must be a political expectation for them to (do so),” said one former Western military officer. “How well they do it, only the USA will currently know (through surveillance and signals intelligence), and time will tell.”

As in the northern Indian Ocean, where Chinese forces operate alongside other nations to combat Somali piracy, current and former officials say all sides are almost certainly quietly spying on and monitoring each other at the same time.

Military secrets, meanwhile, remain the last thing on the minds of those still hoping for news of missing relatives.

“I don’t care about the secrets. I just want my son to return,” Liu Guiqiu, mother of missing passenger Li Le, told China Central Television. (Reporting by Peter Apps in London and Tim Hepher in Paris; Additional reporting by A. Ananthalakshmi; Editing by Will Waterman)